Dynamic protection against failure of a head-end node of one or more TE-LSPs

Abstract

A technique dynamically protects against failure of a head-end node of one or more primary Traffic Engineering Label Switched Paths (TE-LSPs) in a computer network. According to the novel technique, a neighboring upstream node (“protecting node”) of the head-end node learns of the primary TE-LSPs (and their respective state control blocks) extending from the head-end node to one or more address prefixes. The protecting node establishes a repair TE-LSP for each of the primary TE-LSPs to a corresponding downstream neighboring node of the head-end node (a “next-next-hop”). In response to detecting a failure of the head-end node, the protecting node locally reroutes traffic destined for the address prefixes to an appropriate repair TE-LSP. Due to the failure of the head-end node, the protecting node then refreshes the states of the primary TE-LSPs using replicated state control blocks accordingly, until the repair TE-LSPs are no longer needed.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to computer networks and more particularly to protection against failure of a head-end node of one or more Traffic Engineering Label Switched Paths (TE-LSPs) in a computer network. [0003] 2. Background Information [0004] A computer network is a geographically distributed collection of nodes interconnected by communication links and segments for transporting data between end nodes, such as personal computers and workstations. Many types of networks are available, with the types ranging from local area networks (LANs) to wide area networks (WANs). LANs typically connect the nodes over dedicated private communications links located in the same general physical location, such as a building or campus. WANs, on the other hand, typically connect geographically dispersed nodes over long-distance communications links, such as common carrier telephone lines, optical lightpaths, synchronous optica...

AI Technical Summary

Benefits of technology

[0025] Advantageously, the novel technique dynamically protects against failure of a head-end node of one or more primary TE-LSPs in a computer network. By establishing repair TE-LSPs around the head-end node, the novel technique allows a protecting node to quickly reroute traffic onto the repair TE-LSPs to the primary TE-LSPs in the event of head-end node failure. In particular, the use of repair TE-LSPs may increase the recovery scope of provider node (P)-to-P TE-LSP mesh networks, while preserving scalability as compared to provider edge node (PE)-to-PE TE-LSP mesh networks. Also, TE techniques may be advantageously applied to the repair TE-LSPs, as will be understood by those skilled in the art. Further, the dynamic nature of the novel technique alleviates the need for cumbersome manual configuration.

Problems solved by technology

Since management of interconnected computer networks can prove burdensome, smaller groups of computer networks may be maintained as routing domains or autonomous systems.

In certain network configurations (e.g., with a large number of PE routers), however, this results in a large number of TE-LSPs throughout the network.

Occasionally, a network element (e.g., a node or link) fails, causing redirection of the traffic that originally traversed the failed network element to other network elements that bypass the failure.

Reconfiguring a network in response to a network element failure using, e.g., pure IP rerouting, can be time consuming.

As such, there is currently no known method to protect against a failure of the TE-LSP head-end node using FRR.

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